The present invention relates to endoprosthetic elbow joints in the form of a whole endoprosthesis having at least one hinge joint provided with anchoring shanks of which one is to be connected to the humerus and the other of which is to be connected to the ulna of a patient, the axis of the hinge joint taking the place of the flexing and extending axis of the natural arm. Hereinafter such joints will be referred to as "of the kind described".
Endoprosthetic elbow joints of the kind described are not complete replacements for the natural elbow joint since they do not have a part which performs the function of the humeroradial articulation in the elbow region. Existing artificial elbow joints are constructed simply on the principle of a hinge-joint and have one shank to be anchored in the humerus and one shank to be anchored in the ulna, these two bones of the arm having removed from them the damaged parts or parts which would hamper the fitting of the artificial joint before the joint is in fact fitted. An operation on the joint has to be performed and in it the damaged parts of the humeroradial articulation are removed and are either not replaced or else are replaced by parts which are not connected to the hinge joint and which provide only a minimum of the mobility and load bearing capacity of the natural arm. However, in comparison with the natural joint, the overall load bearing capacity of an arm fitted with an artificial joint of this kind falls far short of expectations, in particular as regards the taking up and transmission of pressure or reaction forces acting on the hand, due to the fact that an appropriate proportion of the forces cannot be transmitted via the radius because the relevant part of the joint is missing or inadequate for the purpose.
It is an object of the invention to provide an elbow joint of the kind described in which the radius of the arm retains its ability to transmit pressure forces at the same time as its natural mobility in rotation is preserved.